After "with automatic weights", nose became weird
To me, it looks like a mesh deformation. (Its hard to see in the video :-D )


I don't do much rigging, but under amateur in properties, go to display and check axis.
Check that the axis is Z-up on the nasal bones. 
If it is not, rotate it and re-parent it with automatic weights.
Check that in edit mode the normals are correct along. They shouldn't be though due to your correct texturing.
Check all scales have been applied to the objects. (Object --> Apply --> Scale) It can sometimes deform meshes, particularly when sculpting and rigging.


Other than that, I have no clue.

All the best of luck and hope I helped,

BFB

EDIT: I took a look at your model and I seem to be right. I turned on axes in the amateur pannel. The bones going around the outside of your nostrils are at a -90˚ roll. Set it to 0.